Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Desktop/Android/HTML5/iOS Java game development framework
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
TX Library is a tiny graphics library for Win32 written in C++.
A free Chess program for Windows with a large set of features
Enigma is a puzzle game
2D Open Source MMORPG
2D game development library for Ruby and C++
Android apps.
Vivid is a modern C++ 3D engine using OpenGL4+
2D Game Engine
A 2D game engine and level editor
Vivid Engine 2 is an open source 3D Engine coded using C# and C++.
Cross-platform 2D and 3D game engine
A cross-platform 2D game engine
Paint Program
Real-time RPG for PC/tablet/phone; multiple quests and random dungeons
Montys his name Matching is his game, a game of snap
Build Cross-platform Applications
scriptable game engine with built-in support for 2D graphics and sound
.NET wrapper for the Irrlicht Engine